Method of manufacturing escalator handrail

ABSTRACT

A method of manufacturing an escalator handrail of the invention is characterized by including: a metallic steel-wire producing step of placing a center elemental wire and a plurality of strands so that the plurality of strands surrounds the center elemental wire, and applying tension to them so that each distance between the center elemental wire and each of the strands becomes the same, to thereby produce the metallic steel wire; a preheating step of heating the metallic steel wire to a temperature equal to or more than that of a thermoplastic resin in a molten state; a composite-material forming step of integrating the metallic steel wire heated with the thermoplastic resin in a molten state, and extruding them through a die finished into a cross-section shape of the escalator handrail to thereby form the composite material; and a cooling step of forcibly cooling the composite material.

TECHNICAL FIELD

The present invention relates to a handrail for escalator whichcomprises a composite material, and a manufacturing method of the same.

BACKGROUND ART

Escalator handrails used for escalators comprise composite materialseach including a metallic steel wire, a thermoplastic resin, a canvas,etc., and are profile shape products each comprising the compositematerial in which the metallic steel wire is placed in the thermoplasticresin. In Patent Document 1, there is described a manufacturing methodof a tire which comprises a resin-metal composite material comprising aresin material and a metallic steel wire. According to the resin-metalcomposite material in Patent Document 1, the adhesive strength thereinhas been enhanced using a treatment liquid (special treatment liquid)that contains a silane coupling agent and has a contact angle of 80° orless. The manufacturing method of the resin-metal composite material inPatent Document 1 comprises: applying a solution of the si lane couplingagent, that has been prepared by diluting it with water including analcohol or a surfactant, onto the metallic steel wire followed bysintering at 110° C.; and then subjecting the wire to integral moldingby incorporating it into the resin; so that a pull-out strength of themetallic steel wire relative to the resin is intended to be enhanced.

Further, the tire in Patent Document 1 is described: to use a cord ofmetallic steel wire formed of a mono-filament (single wire) of a metalfiber or a multi-filament (strand wire) provided by twisting such metalfibers; and to be provided as a superior one in adhesion propertybetween the resin material and the metallic steel wire, because of theuse of the special treatment liquid, even when the multi-filament isapplied as the metallic steel wire.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-open No. 2012-11718(Paragraph 0018 to Paragraph 0020, Paragraph 0063, Paragraph 0074, FIG.1)

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Although the metal-fiber single wire or strand wire is used in the tirein Patent Document 1, with respect to the escalator handrail, in orderto enhance its strength, there are cases where a metallic steel wireconfigured with a center elemental wire and a plurality of strands isused. In the case where the metallic steel wire for forming thecomposite material is configured with the center elemental wire and theplurality of strands, and the center elemental wire and the plurality ofstrands are twisted together to provide a strand wire as in PatentDocument 1, a problem arises in that the thermoplastic resin can not beuniformly filled in between the center elemental wire and the strands,resulting in a large variation in pull-out strength of the metallicsteel wire relative to the thermoplastic resin, so that there may be acase where a required pull-out strength can not be ensured, or likewise.

The present invention has been made to solve the problem as describedabove, and an object thereof is, in the escalator handrail using themetallic steel wire configured with the center elemental wire and theplurality of strands, to enhance the pull-out strength of the metallicsteel wire relative to the thermoplastic resin, and to make the pull-outstrength stable.

Means for Solving the Problems

A method of manufacturing an escalator handrail of the invention ischaracterized by including: a metallic steel wire producing step ofplacing a center elemental wire and a plurality of strands so that theplurality of strands surrounds the center elemental wire; and applyingtension to them in an extending direction of the center elemental wireand the strands so that each distance between the center elemental wireand each of the strands becomes the same, to thereby produce themetallic steel wire; a preheating step of heating the metallic steelwire to a temperature equal to or more than that of a thermoplasticresin in a molten state; a composite-material forming step ofintegrating the metallic steel wire heated in the preheating step withthe thermoplastic resin in a molten state, and extruding them through adie finished into a cross-section shape of the escalator handrail tothereby form the composite material; and a cooling step of forciblycooling the composite material formed in the composite-material formingstep.

Effect of the Invention

According to the method of manufacturing an escalator handrail of theinvention, since applying tension to them in the extending direction ofthe center elemental wire and the strands so that each distance betweenthe center elemental wire and each of the strands becomes the same, tothereby produce the metallic steel wire, and integrating the metallicsteel wire with the thermoplastic resin in a molten state, and extrudingthem through a die finished into a cross-section shape of the escalatorhandrail to thereby form the composite material, it is possible toenhance the pull-out strength of the metallic steel wire relative to thethermoplastic resin in the escalator handrail, and to make the pull-outstrength stable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a profile extrusion molding apparatusaccording to Embodiment 1 of the invention.

FIG. 2 is a cross-sectional view of a metallic steel wire according toEmbodiment 1 of the invention.

FIG. 3 is a cross-sectional view of an escalator handrail according toEmbodiment 1 of the invention.

FIG. 4 is an enlarged view around the metallic steel wire in FIG. 3.

FIG. 5 is a cross-sectional view of a handrail intermediate according toEmbodiment 2 of the invention.

FIG. 6 is a cross-sectional view of an escalator handrail according toEmbodiment 2 of the invention.

FIG. 7 is a cross-sectional view of an escalator handrail according toEmbodiment 3 of the invention.

FIG. 8 is a cross-sectional view of another escalator handrail accordingto Embodiment 3 of the invention.

MODES FOR CARRYING OUT THE INVENTION Embodiment 1

FIG. 1 is a diagram showing a profile extrusion molding apparatusaccording to Embodiment 1 of the invention, and FIG. 2 is across-sectional view of a metallic steel wire according to Embodiment 1of the invention. FIG. 3 is a cross-sectional view of an escalatorhandrail according to Embodiment 1 of the invention, and FIG. 4 is anenlarged view around the metallic steel wire in FIG. 3. A profileextrusion molding apparatus 20 includes: an extrusion molding unit 21 toperform extrusion molding in order to shape into an escalator handrail30; a cooling unit 23 to cool an extrusion molded intermediate; a drawerdriving unit 24 to draw the extrusion molded intermediate after passingthrough the cooling unit 23 and getting hardened; and a storage unit 25to store the escalator handrail 30. As shown in FIG. 3, the escalatorhandrail 30 comprises a thermoplastic resin 10, a canvas 11 and ametallic steel wire 3.

The escalator handrail 30 comprises a composite material including themetallic steel wire 3, the thermoplastic resin 10 and the canvas 11, andis a profile shape product comprising the composite material in whichthe metallic steel wire 3 is placed inside the thermoplastic resin 10.With respect to an elongated-shape object that is always associated withits bending and deformation, like the escalator handrail 30, it isrequired in view of its use, to have flexibility and strong pull-outstrength of the metallic steel wire 3. For this reason, as the escalatorhandrail 30, a profile extrusion molded product comprising amain-construction material and a sub-construction material is used. Themain-construction material of the escalator handrail 30 is thethermoplastic resin 10 and the sub-construction material thereof is themetallic steel wire 3. The escalator handrail 30 that is associated withits bending or deforming motion is allowed to run straight when anexternal force applied to the thermoplastic resin 10 as themain-construction material is surely transferred to the metallic steelwire 3 as the sub-construction material placed inside. In this respect,in order that the metallic steel wire 3 as the sub-construction materialmay serve as a main strength member, the metallic steel wire 3 placedinside the thermoplastic resin 10 has to ensure sufficient adhesivestrength to the resin material around the metallic steel wire 3. Thisadhesive strength can be defined as a pull-out strength of the metallicsteel wire 3 relative to the thermoplastic resin 10, in consideration ofthe function of the escalator handrail 30.

As shown in FIG. 2, the metallic steel wire 3 includes a centerelemental wire 8 and a plurality of strands 9. The plurality of strands9 is placed so as to surround the center elemental wire 8. The distancebetween the center elemental wire 8 and each of the strands 9 means adistance between the center of the center elemental wire 8 and thecenter of the strand 9, and that distance is the same at every positionin an extending direction of the center elemental wire 8 and the strands9. Note that the meaning of “the same” for the distance includes“approximately the same (nearly the same)”. The “approximately the same”means that the distance falls within an acceptable range inconsideration of a tolerance due to winding tightness or looseness atthe time of forming the metallic steel wire 3. In the center elementalwire 8 and the strands 9, tension is kept in the extending direction ofthe center elemental wire 8 and the strands 9. The tension in the centerelemental wire 8 and the strands 9 will be described later. As shown inFIG. 4, the thermoplastic resin 10 is uniformly filled in between thecenter elemental wire 8 and the plurality of strands 9 in the metallicsteel wire 3 without forming a void. Shown in FIG. 2 and FIG. 4 is anexample of the metallic steel wire 3 in which six strands 9 are placedto surround the center elemental wire 8 that is single. Note that inFIG. 3, the center elemental wire 8 and the plurality of strands 9 areomitted from illustration, and a region of a broken circle 15illustrated in FIG. 4 is shown as the metallic steel wire 3.

Such a state where the thermoplastic resin 10 is uniformly filled inbetween the center elemental wire 8 and the plurality of strands 9 inthe metallic steel wire 3 as described above, is a preferable state.However, in the conventional art, when a metallic steel wire comprises astrand wire in which a center elemental wire and a plurality of strands9 are twisted together, as is different from the present invention, aresin is not uniformly filled around the center elemental wire,resulting in unstable adhesive strength. Accordingly, description willbe made in detail about a technology for solving conventionalinstability in the pull-out strength of the metallic steel wire 3relative to the thermoplastic resin 10, namely, a technology forenhancing the pull-out strength of the metallic steel wire 3 relative tothe thermoplastic resin 10 and making the pull-out strength stable.

Main units of the profile extrusion molding apparatus 20 will bedescribed. The extrusion molding unit 21 of the profile extrusionmolding apparatus 20 is configured with: an extrusion molding machine 6(thermoplastic resin injector) to inject the thermoplastic resin 10 asone part of the composite material; a canvas feeding reel 2 to feed thecanvas 11 as another part of the composite material; a metallicsteel-wire feeding device 22 to feed the metallic steel wire 3 as stillanother part of the composite material; a preheat device 4 to heat thesethree molding materials; and a die 5, that is a mold to mold, forcollectively taking the three molding materials in a heated statefollowed by forming them into a predetermined shape.

The metallic steel-wire feeding device 22 executes a producing step ofthe metallic steel wire 3 (metallic steel-wire producing step). Themetallic steel-wire feeding device 22 is a device to produce themetallic steel-wire 3 and feed it to the preheat device 4, and isprovided with a plurality of reels 1 on which metallic wiring members asthe materials for the center elemental wire 8 and the strands 9 arewound. As shown in FIG. 2, the center elemental wire 8 and the strands 9are each provided by twisting four metallic wiring members together. Themetallic steel-wire feeding device 22 uses four reels among the reels 1in order to produce a single center elemental wire 8 or a single strand9. In order to produce the metallic steel wire 3 including the singlecenter elemental wire 8 and the six strands 9 as shown in FIG. 2, it isrequired seven reel sets each comprising the four reels 1. In FIG. 1,only four reel sets for producing three strands 9 and the single centerelemental wire 8 are shown, and the remaining three reel sets areomitted from illustration.

The metallic steel-wire feeding device 22 performs control of thetensile force for the metallic steel wire 3 to such an extent that gapsare established between the center elemental wire 8 and the strands 9.Performing such control makes it possible to form gaps between thecenter elemental wire 8 and the strands 9 that can be filled with thethermoplastic resin 10 in a molten state, so that the thermoplasticresin 10 can be fully filled in between the center elemental wire 8 andthe strands 9.

The above control of the tensile force will be described in detail. Atthe time of manufacturing an escalator handrail 30, tensile forcecontrol for a metallic steel wire 3 has always been performed by ametallic steel-wire feeding device 22. When the tensile force for themetallic steel wire 3 is large at the time of extrusion-molding themetallic steel wire 3 and the thermoplastic resin 10 to thereby producea composite material, the metallic steel wire 3 is stretched so that thegap between the center elemental wire 8 and the strand 9 is reduced orthe gap is eliminated, and thus, the thermoplastic resin 10 in a moltenstate is not fully filled around the center elemental wire 8 and thestrand 9. When the thermoplastic resin 10 is not fully filled around thecenter elemental wire 8 and the strand 9, the pull-out strength of themetallic steel wire 3 relative to the thermoplastic resin 10 is lowered,resulting in unstable composite material.

In order to avoid the above problem, the metallic steel-wire feedingdevice 22 performs control of the tensile force for the metallic steelwire 3 so that sufficient gaps are established between the centerelemental wire 8 and the strands 9. By controlling the tensile force, asdescribed previously, the metallic steel-wire feeding device 22 can formthe gaps between the center elemental wire 8 and the strands 9 in themetallic steel wire 3 that can be filled with the thermoplastic resin 10in a molten state, so that the thermoplastic resin 10 can be fullyfilled in between the center elemental wire 8 and the strands 9.

After the metallic steel wire 3 is produced using the metallicsteel-wire feeding device 22, the preheat device 4 executes a step ofpreheating the metallic steel wire 3 (preheating step) just beforesubjected to integral molding with the thermoplastic resin 10. Thepreheat device 4 is a device that heats the metallic steel wire 3 andthe canvas 11. With this device, the metallic steel wire 3 can beinserted into the die 5 at a temperature equivalent to or more than(temperature equal to or more than) the temperature of the thermoplasticresin 10 extruded from the extrusion molding machine 6. Because themetallic steel wire 3 is maintained at a temperature equivalent to ormore than the temperature of the thermoplastic resin 10, it is preventedthat heat in the thermoplastic resin 10 is taken by the metallic steelwire 3 so that the thermoplastic resin 10 is lowered in temperature toget solidified, even at the time the metallic steel wire 3 is in contactwith the thermoplastic resin 10 in the die 5. When the metallic steelwire 3 is maintained at a temperature equivalent to or more than thetemperature of the thermoplastic resin 10, even in the die 5, thethermoplastic resin 10 can keep a uniform viscosity and fluidityequivalent to that at the time it is extruded from the extrusion moldingmachine 6.

The extrusion molding machine 6 executes a step of feeding thethermoplastic resin 10 (resin feeding step) to the die 5. The extrusionmolding machine 6 shown in FIG. 1 performs control of an injectionpressure of the thermoplastic resin 10 for extruding the thermoplasticresin 10. The extrusion molding machine 6 is provided with athermoplastic-resin pellet inserter 12 to insert a thermoplastic-resinpellet in a thermoplastic-resin pellet insertion port 7, and acontroller (unshown) to perform control of the injection pressure of thethermoplastic resin 10. Because the extrusion molding machine 6 performscontrol of the injection pressure of the thermoplastic resin 10, theplacement configuration of the center elemental wire 8 and the strands 9in the metallic steel wire 3 is mostly unchanged, so that thethermoplastic resin 10 can be fully filled in the gaps in the metallicsteel wire 3. The injection pressure of the thermoplastic resin 10 iscontrolled so that the distances between the center elemental wire 8 andthe strands 9 are kept within an allowable range, and a void due to lossof the thermoplastic resin 10 is not formed between the center elementalwire 8 and the strands 9. Note that in FIG. 2 and FIG. 4, an interspaceis illustrated among four metallic wiring members in each of the centerelemental wire 8 and the strands 9; however, the four metallic wiringmembers are twisted together, so that the thermoplastic resin 10 is notfilled in the interspace among the four metallic wiring members.

The above control of the injection pressure will be described in detail.When the injection pressure of the thermoplastic resin 10 is high, theplacement configuration of the center elemental wire 8 and the strands 9in the metallic steel wire 3 may be changed, and in some cases, the gapbetween the center elemental wire 8 and the strand 9 is eliminated. Whenthe gap between the center elemental wire 8 and the strand 9 is reducedor the gap is eliminated, the thermoplastic resin 10 in a molten stateis not fully filled around the center elemental wire 8 and the strand 9.When the thermoplastic resin 10 is not fully filled around the centerelemental wire 8 and the strand 9, the pull-out strength of the metallicsteel wire 3 relative to the thermoplastic resin 10 is lowered,resulting in unstable composite material.

Meanwhile, the injection pressure of the thermoplastic resin 10 is low,a void due to loss of the thermoplastic resin 10 may occur between thecenter elemental wire 8 and the strands 9 in the metallic steel wire 3,so that the thermoplastic resin 10 in a molten state is not fully filledaround the center elemental wire 8 and the strand 9. Like the case wherethe injection pressure of the thermoplastic resin 10 is high, thislowers the pull-out strength of the metallic steel wire 3 relative tothe thermoplastic resin 10, resulting in unstable composite material.

In order to avoid the above problem, the extrusion molding machine 6performs control of the injection pressure of the thermoplastic resin10. Because the extrusion molding machine 6 performs control of theinjection pressure of the thermoplastic resin 10 so that

the distances between the center elemental wire 8 and the strands 9 arekept within an allowable range and the void due to loss of thethermoplastic resin 10 is not formed between the center elemental wireand the strands 9, the placement configuration of the center elementalwire 8 and the strands 9 in the metallic steel wire 3 is mostlyunchanged, so that the thermoplastic resin 10 can be fully filled in thegaps in the metallic steel wire 3.

Meanwhile, the thermoplastic-resin pellet insertion port 7 and theinside of the extrusion molding machine 6 are set to a temperature atwhich the thermoplastic resin 10 is molten. If the thermoplastic resin10 does not reach its melting temperature, the thermoplastic resin 10 isnot molten, so that the thermoplastic resin 10 is not filled in themetallic steel wire 3.

For this reason, in the extrusion molding machine 6 according to thepresent invention, a temperature control is performed by setting atemperature that is equal to or more than the melting temperature of thethermoplastic resin 10, but less than the decomposition temperature ofthe thermoplastic resin 10. By thus performing the temperature control,water included in the thermoplastic resin 10 can be evaporated offbecause the melting temperature of the thermoplastic resin 10 is higherthan the boiling point of water. Accordingly, in the extrusion moldingmachine 6 being set equal to or more than the melting temperature of thethermoplastic resin 10, the moisture contained in the thermoplasticresin 10 is evaporated off, and thus the escalator handrail 30 can bemanufactured with a low moisture-content rate. When the moisture-contentrate is controlled to be low in the extrusion molding machine 6, theescalator handrail 30 becomes able to mitigate its degradation due tothe moisture internally contained in the escalator handrail 30.

The die 5 combines the metallic steel wire 3, the thermoplastic resin 10and the canvas 11 to thereby execute a step of forming the compositematerial (composite-material forming step). In the die 5, itscross-section shape through which the composite material is extruded,has been finished into the cross-section shape of the escalator handrail30. For the die 5 shown in FIG. 1, its internal temperature iscontrolled to a temperature at which the thermoplastic resin 10 ismolten. When the temperature in the die is controlled to be equal to thetemperature at which the thermoplastic resin 10 is molten, the die 5 cankeep unchanged the temperatures of the metallic steel wire 3 preheatedby the preheat device 4 and the thermoplastic resin 10 fed from theextrusion molding machine 6, so that the thermoplastic resin 10 can befilled in between the center elemental wire 8 and the strands 9 in themetallic steel wire 3 without occurrence of a void due to loss of thethermoplastic resin 10. Because a void due to loss of the thermoplasticresin 10 does not occur between the center elemental wire 8 and thestrands 9 in the metallic steel wire 3, the composite material producedfrom the die 5 is well-suited to the escalator handrail 30 configuredwith the metallic steel wire 3, the thermoplastic resin 10 and thecanvas 11. Because a void due to loss of the thermoplastic resin 10 doesnot occur between the center elemental wire 8 and the strands 9 in themetallic steel wire 3, the escalator handrail using the compositematerial produced from the die 5 is enhanced in the pull-out strength ofthe metallic steel wire 3 relative to the thermoplastic resin 10, and ismade stable in the pull-out strength.

The above temperature control of the die 5 will be described in detail.When the temperature of the die 5 is not set to the melting temperatureof the thermoplastic resin 10, the temperature of the thermoplasticresin 10 ejected from the extrusion molding machine 6 is lowered so thatthe thermoplastic resin 10 gets solidified; further, the metallic steelwire 3 having been preheated and coming out of the preheat device 4 isalso cooled, making the viscosity and fluidity of the thermoplasticresin 10 lower. When the viscosity and fluidity of the thermoplasticresin 10 is lowered, a void due to loss of the thermoplastic resin 10occurs between the center elemental wire 8 and the strands 9 in themetallic steel wire 3, so that the thermoplastic resin 10 is not fullyfilled in the metallic steel wire 3.

In order to avoid the above problem, the die 5 is controlled to be at atemperature at which the thermoplastic resin 10 is molten. The die 5,when its internal temperature is controlled to the temperature at whichthe thermoplastic resin 10 is molten, can keep unchanged thetemperatures of the metallic steel wire 3 and the thermoplastic resin10, so that the thermoplastic resin 10 can be filled in between thecenter elemental wire 8 and the strands 9 in the metallic steel wire 3without occurrence of a void due to loss of the thermoplastic resin 10.Because a void due to loss of the thermoplastic resin 10 does not occurbetween the center elemental wire 8 and the strands 9 in the metallicsteel wire 3, the composite material produced from the die 5 iswell-suited to the escalator handrail 30 configured with the metallicsteel wire 3, the thermoplastic resin 10 and the canvas 11. Because avoid due to loss of the thermoplastic resin 10 does not occur betweenthe center elemental wire 8 and the strands 9 in the metallic steel wire3, the escalator handrail 30 manufactured by the profile extrusionmolding apparatus 20 is enhanced in the pull-out strength of themetallic steel wire 3 relative to the thermoplastic resin 10, and ismade stable in the pull-out strength.

Description will be made about the steps of forming the escalatorhandrail 30 by use of the above profile extrusion molding apparatus 20.

The metallic steel-wire feeding device 22 produces the metallic steelwire 3 and sends out the metallic steel wire 3 toward the downstreamside (metallic steel-wire producing step). The metallic steel wire 3produced by the metallic steel-wire feeding device 22 and the canvas 11coming out of the canvas feeding reel 2 are heated in the preheat device4 to a temperature equivalent to or more than the melting temperature ofthe thermoplastic resin 10 so that, in the die 5, they become at atemperature that is the same as the melting temperature of thethermoplastic resin 10 (preheating step). The thermoplastic resin 10whose temperature and injection pressure are being controlled is fedfrom the extrusion molding machine 6 to the die 5 (resin feeding step),so that, in the die 5, the metallic steel wire 3 and the canvas 11 inthe heated state are joined with the thermoplastic resin 10 in a moltenstate, at the temperature same as that of the thermoplastic resin. Afterthe metallic steel wire 3, the canvas 11 and the thermoplastic resin 10are joined together, from the inside of the die 5, the compositematerial in which the metallic steel wire 3, the thermoplastic resin 10and the canvas 11 are integrated together, is extruded into the shape ofthe escalator handrail 30 (composite-material forming step), which isthen forcibly subjected to cooling (forced cooling) by way of coolingwater in the cooling unit 23 in order to maintain its shape (coolingstep). After cooling, the escalator handrail 30 provided as thecomposite material in a hardened state is drawn out by the drawerdriving unit 24, and then the escalator handrail 30 is stored in thestorage unit 25 (storing step).

The preheat device 4 and the die 5 shown in FIG. 1 are arranged so thatthe temperature during transportation from the preheat device 4 to thedie 5, is not lowered to less than the melting temperature of thethermoplastic resin 10. Note that, in the case where the preheat device4 is arranged close to the die 5 so that the temperature of the metallicsteel wire 3 and the canvas 11 in a heated state does not lowered duringtransportation from the preheat device 4 to the die 5, the temperaturefor heating the metallic steel wire 3 and the canvas 11 by the preheatdevice 4 may be set to a temperature equal to the melting temperature ofthe thermoplastic resin 10.

Because the preheat device 4 and the die 5 under temperature control areprovided, the metallic steel wire 3 of Embodiment 1 can be deliveredfrom the preheat device 4 to the die 5 without lowering its temperature,and the temperature of the metallic steel wire 3 can be maintained to atemperature equivalent to or more than the temperature of thethermoplastic resin 10 (within a temperature range where a temperatureis equal to or more than the melting temperature of the thermoplasticresin but less than its decomposition temperature).

Because the temperature of the metallic steel wire 3 is maintained to atemperature equivalent to or more than the temperature of thethermoplastic resin 10 (within a temperature range where a temperatureis equal to or more than the melting temperature of the thermoplasticresin but less than its decomposition temperature), even at the time thethermoplastic resin 10 of Embodiment 1 is in contact with the metallicsteel wire 3 in the die 5, there is no case where its heat is taken bythe metallic steel wire 3 so that the thermoplastic resin 10 is loweredin temperature to get solidified; thus, the thermoplastic resin 10 cankeep a uniform viscosity and fluidity equivalent to that at the time itis extruded from the extrusion molding machine 6.

Thus, according to the escalator handrail 30 of Embodiment 1, becausethe temperature of the metallic steel wire 3 and the temperature of thethermoplastic resin 10 are made the same in the process of the profileextrusion molding using the composite material, the thermoplastic resin10 can be uniformly and fully filled in between the center elementalwire 8 and the strands 9 in the metallic steel wire 3 without causingsolidification of the thermoplastic resin 10 in the die 5, so that it ispossible to enhance the pull-out strength of the metallic steel wire 3relative to the thermoplastic resin 10. Note that the meaning of “thesame” for the temperature includes “approximately the same (nearly thesame)”. The “approximately the same” means that the temperature fallswithin an acceptable range in consideration of a tolerance. According tothe escalator handrail 30 of Embodiment 1, because the pull-out strengthof the metallic steel wire 3 relative to the thermoplastic resin 10 isenhanced, it is possible to make the pull-out strength stable for a longperiod of time.

The profile extrusion molding apparatus 20 in Embodiment 1 performscontrol of the injection pressure and temperature of the thermoplasticresin 10 in the process of the profile extrusion molding using thecomposite material, so that when the thermoplastic resin 10 is extrudedinto the die 5, the thermoplastic resin 10 can be uniformly and fullyfilled in the metallic steel wire 3 without occurrence of a void due toloss of the thermoplastic resin 10 between the center elemental wire 8and the strands 9 in the metallic steel wire 3. The profile extrusionmolding apparatus 20 in Embodiment 1 can manufacture the escalatorhandrail 30 which is enhanced in the pull-out strength of the metallicsteel wire 3 relative to the thermoplastic resin 10 and is made stablein the strength as the composite material, namely, the escalatorhandrail 30 with an enhanced quality.

As described above, according to the escalator handrail 30 of Embodiment1, it is characterized in that: the metallic steel wire 3 comprises thecenter elemental wire 8 and the plurality of strands 9 placed so as tosurround the center elemental wire 8; the distance between the centerelemental wire 8 and each of the strands 9 is the same at every positionin the extending direction of the center elemental wire 8 and thestrands 9; and the thermoplastic resin 10 is filled in between thecenter elemental wire 8 and the strands 9 without forming a void. Thus,it is possible to enhance the pull-out strength of the metallic steelwire 3 relative to the thermoplastic resin 10 in the escalator handrail30, and to make the pull-out strength stable.

According to the method of manufacturing an escalator handrail ofEmbodiment 1, it is characterized by including: the metallic steel-wireproducing step of placing the center elemental wire 8 and the pluralityof strands 9 so that the plurality of strands surrounds the centerelemental wire 8, and applying tension to them in the extendingdirection of the center elemental wire 8 and the strands 9 so that eachdistance between the center elemental wire 8 and each of the strands 9becomes the same, to thereby produce the metallic steel wire 3; thepreheating step of heating the metallic steel wire 3 to a temperatureequal to or more than that of the thermoplastic resin 10 in a moltenstate; the composite-material forming step of integrating the metallicsteel wire 3 heated in the preheating step with the thermoplastic resin10 in a molten state, and extruding them through the die 5 finished intothe cross-section shape of the escalator handrail 30 to thereby form thecomposite material; and the cooling step of forcibly cooling thecomposite material formed in the composite-material forming step. Thus,it is possible to manufacture the escalator handrail 30 which isenhanced in the pull-out strength of the metallic steel wire 3 relativeto the thermoplastic resin 10 and is made stable in the pull-outstrength, namely, the escalator handrail 30 with an enhanced quality.

Embodiment 2

FIG. 5 is a cross-sectional view of a handrail intermediate according toEmbodiment 2 of the invention, and FIG. 6 is a cross-sectional view ofan escalator handrail according to Embodiment 2 of the invention. Anescalator handrail 30 of Embodiment 2 is a product by a multi-layermolding. For the escalator handrail 30 of Embodiment 2, firstly, themetallic steel wire 3, the thermoplastic resin 10 and the canvas 11 areintegrally molded in the die 5 and then cooled, to accomplish afirst-layer molding. The product after completion of the first-layermolding is a handrail intermediate 26. After performing the first-layermolding, in order to get rigidity, a thermoplastic resin 28 that is thesame material as the thermoplastic resin 10, is thick coated over anexposed portion 27 of the thermoplastic resin 10 that is on an oppositeside to the canvas 11 in the handrail intermediate 26, to therebyaccomplish the multi-layer molding. As shown in FIG. 6, the escalatorhandrail 30 of Embodiment 2 comprises the handrail intermediate 26 andthe thermoplastic resin 28.

At the time of performing the first-layer molding, the thermoplasticresin 10 is set to have a predetermined thickness to the extent that itcovers the metallic steel wire 3. Specifically, a first thermoplasticresin (thermoplastic resin 10) covering the metallic steel wire 3 in thehandrail intermediate 26 has a thickness from its inner face that willbe facing to the escalator to which the escalator handrail 30 is to befitted (on the side where the canvas 11 is attached), to the outer faceof the exposed portion 27 that is on an opposite side to the inner face,which is the above predetermined thickness and is, for example, withintwice a height of the metallic steel wire 3 in a thickness direction ofthe first thermoplastic resin (thermoplastic resin 10). The smaller thevolume of the thermoplastic resin 10, the faster the cooling speed ofthe handrail intermediate 26 after coming out of the die 5, and themetallic steel wire 3 is immobilized by the thermoplastic resin 10 in ahardened state. Accordingly, the thermoplastic resin 10 filled in themetallic steel wire 3 becomes tighter, so that the pull-out strength isenhanced. According to the escalator handrail 30 of Embodiment 2, likeEmbodiment 1, it becomes possible to place the center elemental wire 8and each of the strands 9 not to be in contact with each other, and alsoto place the plurality of strands 9 not to be in contact with eachother.

Embodiment 3

The thermoplastic resin 10 is injected through the extrusion moldingmachine 6 into the die 5. In Embodiment 3, description will be madeabout an escalator handrail 30 in which, because of making optimizationof the internal temperature of the extrusion molding machine 6, thethermoplastic resin filled in the metallic steel wire 3 is tighter andthus the pull-out strength is higher than those in Embodiment 1 andEmbodiment 2.

FIG. 7 is a cross-sectional view of an escalator handrail according toEmbodiment 3 of the invention, and FIG. 8 is a cross-sectional view ofanother escalator handrail according to Embodiment 3 of the invention.In Embodiment 3, the extrusion molding machine 6 is heated so that itsinternal temperature reaches an upper-limit temperature at whichdecomposition of a thermoplastic resin 29 that is the same material asthe thermoplastic 10 is not initiated. The thermoplastic resin 29 has aproperty such that its viscosity is lowered as the temperature becomeshigher, so that when the inside of the extrusion molding machine 6 isset to a higher temperature, the viscosity of the thermoplastic resin 29passing through the extrusion molding machine 6 is lowered. When theinside of the extrusion molding machine 6 is set to a higher temperatureso as to use the thermoplastic resin 29 whose viscosity is lowered to aminimum value without undergoing decomposition, the thermoplastic resin29 becomes well-penetrated into the metallic steel wire 3 in the die 5,so that the thermoplastic resin 29 is fully filled around the centerelemental wire 8 and the strand 9, and thus the pull-out strength of themetallic steel wire 3 relative to the thermoplastic resin 29 isenhanced.

According to the escalator handrail 30 of Embodiment 3, thethermoplastic resin 29 whose viscosity is lowered to a minimum valuewithout undergoing decomposition has been used, so that thethermoplastic resin 29 filled in the metallic steel wire 3 becomestighter and thus the pull-out strength becomes higher than those inEmbodiment 1 and Embodiment 2.

It should be noted that unlimited combination of the respectiveembodiments and an appropriate modification/omission in the embodimentsmay be made in the present invention without departing from the scope ofthe invention.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

3: metallic steel wire, 5: die, 8: center elemental wire, 9: strand, 10:thermoplastic resin, 27: exposed portion, 28: thermoplastic resin, 29:thermoplastic resin, 30: escalator handrail.

The invention claimed is:
 1. A method of manufacturing an escalatorhandrail which includes a composite material having a metallic steelwire and a thermoplastic resin, comprising: a metallic steel-wireproducing step of placing a center elemental wire and a plurality ofstrands so that the plurality of strands surrounds the center elementalwire, and applying tension to the center elemental wire and strands inan extending direction of the center elemental wire and the strands sothat each distance between the center elemental wire and each of thestrands becomes the same, to thereby produce the metallic steel wire; apreheating step of heating the metallic steel wire, prior to integrationwith the thermoplastic resin, to a temperature equal to or more thanthat of the thermoplastic resin in a molten state; a composite-materialforming step of integrating the metallic steel wire, while it is at thetemperature equal to or more than that of the thermoplastic resin in themolten state, with the thermoplastic resin in a molten state, andextruding them through a die finished into a cross-section shape of theescalator handrail to thereby form the composite material; and a coolingstep of forcibly cooling the composite material formed in thecomposite-material forming step.
 2. The method of manufacturing anescalator handrail of claim 1, wherein, in the composite-materialforming step: an internal temperature of the die is controlled to be thesame as the temperature of the thermoplastic resin in a molten state;and an injection pressure of the thermoplastic resin in a molten stateinjected into the die is controlled so that the distance between thecenter elemental wire and each of the strands is kept within anallowable range, and a void due to loss of the thermoplastic resin isnot formed between the center elemental wire and the strands.
 3. Themethod of manufacturing an escalator handrail of claim 1, wherein thethermoplastic resin to be fed at the time of the composite-materialforming step is heated so as to have a viscosity lowered to a minimumvalue without undergoing decomposition.
 4. The method of manufacturingan escalator handrail of claim 2, wherein the thermoplastic resin to befed at the time of the composite-material forming step is heated so asto have a viscosity lowered to a minimum value without undergoingdecomposition.